combobox with disabled items?

[jodleren]

Hi!

Is there a way for doing this?

I can draw items as i want, but having items not selectable? Is that
possible?

WBR
Sonnich

[alang...@aol.com]

const
CB1DisabledIndices = [2, 5];

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
if (ComboBox1.ItemIndex in CBDisabledIndices) then
ComboBox1.ItemIndex := -1;
end;

This uses a set for multiple disabling, but if you have only one
then . . .

const
CB1DisabledIndex = 2;

if (ComboBox1.ItemIndex = CBDisabledIndex) then
etc

And when you draw the items if they're disabled then draw them a
different colour.

Alan Lloyd

[BRoberts]

<alang...@aol.com> wrote in message
news:2bcf49a9-e5f4-4396...@22g2000yqr.googlegroups.com...

An alternative to using a separate structure to track item status would be
to use the Items.Objects property:

ComboBox1.Items.Objects [n] := tObject (EnabledValueOfItemN)

or

ComboBox1.Items.AddObject (ItemCaption, tObject (ItemEnabledState))

then

if Boolean (ComboBox1.Items.Object [n]) then // it's enabled

An alternative to setting the ItemIndex to -1 when a disabled item is
selected would be to track the previous value:

In onClick

if not Boolean (ComboBox1.Items.Objects [Combobox1.ItemIndex])
then ComboBox1.ItemIndex := cb1LastIndex;
cbLastIndex := ComboBox1.ItemIndex;

where cbLastIndex is declared in the private section of the form as an
integer.

[alang...@aol.com]

On 22 Jan, 01:17, "BRoberts" <berdontem...@caneris.ca> wrote:
>
> An alternative to using a separate structure to track item status would be
> to use the Items.Objects property:
>
> � � ComboBox1.Items.Objects [n] := tObject (EnabledValueOfItemN)
>
> or
>
> � � ComboBox1.Items.AddObject (ItemCaption, tObject (ItemEnabledState))
>
> then
>
> � � if Boolean (ComboBox1.Items.Object [n]) then // it's enabled
>

A good idea, particularly if the disabled items are set dynamically
during program interaction.

OTOH if there are more than 1 disabled items, or if they have to be
set to a default, I think using a set and setting the Objects[] in a
loop is clearer.

DisabledItems = [3, 5, 7];

for i := 0 to MyComboBox.items.Count - 1 do
if i in DisabledItems then . . .

> An alternative to setting the ItemIndex to -1 when a disabled item is
> selected would be to track the previous value:
>
> In onClick
>
> � � if not Boolean (ComboBox1.Items.Objects [Combobox1.ItemIndex])
> � � then ComboBox1.ItemIndex := cb1LastIndex;
> � � cbLastIndex := ComboBox1.ItemIndex;
>
> where cbLastIndex is declared in the private section of the form as an
> integer.

Good technique.

Alan Lloyd